From: Arnd Bergmann <arnd@arndb.de>
To: Tony Lindgren <tony@atomide.com>
Cc: Daniel Lezcano <daniel.lezcano@linaro.org>,
linux-arm-kernel@lists.infradead.org, balbi@ti.com,
Alexandre Courbot <gnurou@gmail.com>,
Stephen Warren <swarren@wwwdotorg.org>,
Linux Kernel Mailing List <linux-kernel@vger.kernel.org>,
Thierry Reding <thierry.reding@gmail.com>,
linux-tegra@vger.kernel.org, tglx@linutronix.de,
Linux OMAP Mailing List <linux-omap@vger.kernel.org>
Subject: Re: [RFC/PATCH 00/11] arm: omap: counter32k rework
Date: Mon, 05 Oct 2015 13:03:52 +0200 [thread overview]
Message-ID: <9068678.D8T0aRhgnK@wuerfel> (raw)
In-Reply-To: <20151005105554.GV23801@atomide.com>
On Monday 05 October 2015 03:55:55 Tony Lindgren wrote:
> * Daniel Lezcano <daniel.lezcano@linaro.org> [151001 15:16]:
> > On 09/30/2015 04:49 PM, Arnd Bergmann wrote:
> > >On Wednesday 30 September 2015 16:42:21 Arnd Bergmann wrote:
> > >>
> > >>TEGRA folks: the tegra_read_persistent_clock() implementation apparently
> > >>predates the Tegra RTC driver and I wonder if they actually do the
> > >>right thing in combination. Could it be that the wall time forwards
> > >>twice as fast as it should during resume when the RTC driver is loaded?
> > >>Could it be that we can simply remove tegra_read_persistent_clock()
> > >>and the register_persistent_clock() infrastructure?
> > >>
> > >
> > >I found the 'sleeptime_injected' variable now, which takes care of
> > >forwarding the clock by the correct amount.
> > >
> > >I also found the CLOCK_SOURCE_SUSPEND_NONSTOP flag next to it, which
> > >should let us use the counter32k driver to provide the correct
> > >time during suspend without the omap_read_persistent_clock() function.
> > >We should be able to just delete that code.
> > >
> > >If we decide to also delete the tegra_read_persistent_clock()
> > >function, we can remove the registration too.
> >
> >
> > +1
>
> We could maybe have read_persistent_clock() just check for the
> CLOCK_SOURCE_SUSPEND_NONSTOP flag?
timekeeping_resume() already ignores the persistent clock values if
the clocksource has this set. Do you mean we should additionally
not call the read_persistent_clock() function at all to safe a
few cycles reading that value?
How expensive is the function?
Arnd
next prev parent reply other threads:[~2015-10-05 11:04 UTC|newest]
Thread overview: 44+ messages / expand[flat|nested] mbox.gz Atom feed top
2015-09-29 20:43 [RFC/PATCH 00/11] arm: omap: counter32k rework Felipe Balbi
2015-09-29 20:43 ` [RFC/PATCH 01/11] arm: omap2: timer: get rid of obfuscating macros Felipe Balbi
2015-09-29 20:43 ` [RFC/PATCH 02/11] arm: omap2: timer: add a gptimer argument to sync32k_timer_init() Felipe Balbi
2015-09-29 20:43 ` [RFC/PATCH 03/11] arm: omap2: timer: remove __omap_gptimer_init() Felipe Balbi
2015-10-05 11:01 ` Tony Lindgren
2015-10-05 15:24 ` Felipe Balbi
2015-10-05 16:02 ` Tony Lindgren
2015-10-05 16:08 ` Felipe Balbi
2015-10-05 16:30 ` Tony Lindgren
2015-09-29 20:43 ` [RFC/PATCH 04/11] arm: omap2: timer: provide generic sync32k_timer_init function Felipe Balbi
2015-09-29 20:44 ` [RFC/PATCH 05/11] arm: omap2: timer: move realtime_counter_init() around Felipe Balbi
2015-09-29 20:44 ` [RFC/PATCH 06/11] arm: omap2: timer: always call clocksource_of_init() when DT Felipe Balbi
2015-09-29 20:44 ` [RFC/PATCH 07/11] arm: omap2: timer: remove omap4_local_timer_init Felipe Balbi
2015-09-29 20:44 ` [RFC/PATCH 08/11] arm: omap2: timer: rename omap_sync32k_timer_init() Felipe Balbi
2015-09-29 20:44 ` [RFC/PATCH 09/11] clocksource: add TI 32.768 Hz counter driver Felipe Balbi
2015-10-01 21:58 ` John Stultz
2015-10-01 21:59 ` Daniel Lezcano
2015-10-05 10:50 ` Tony Lindgren
2015-10-05 11:03 ` Tony Lindgren
2015-10-01 22:20 ` John Stultz
2015-10-01 22:30 ` Felipe Balbi
2015-09-29 20:44 ` [RFC/PATCH 10/11] arm: omap2: timer: limit hwmod usage to non-DT boots Felipe Balbi
2015-09-29 20:44 ` [RFC/PATCH 11/11] arm: boot: dts: omap: add missing default status for 32k counter Felipe Balbi
2015-09-30 8:15 ` Arnd Bergmann
2015-09-30 14:12 ` Felipe Balbi
2015-09-30 21:58 ` Arnd Bergmann
2015-10-05 17:52 ` Felipe Balbi
2015-10-05 19:41 ` Felipe Balbi
2015-10-06 8:08 ` Arnd Bergmann
2015-10-06 14:57 ` Felipe Balbi
2015-10-06 15:18 ` Tony Lindgren
2015-10-06 15:29 ` Felipe Balbi
2015-10-05 10:45 ` Tony Lindgren
2015-09-30 8:22 ` [RFC/PATCH 00/11] arm: omap: counter32k rework Arnd Bergmann
2015-09-30 14:13 ` Felipe Balbi
2015-09-30 14:42 ` Arnd Bergmann
2015-09-30 14:49 ` Arnd Bergmann
2015-09-30 14:57 ` Felipe Balbi
2015-09-30 15:03 ` Thierry Reding
2015-10-01 22:12 ` Daniel Lezcano
2015-10-05 10:55 ` Tony Lindgren
2015-10-05 11:03 ` Arnd Bergmann [this message]
2015-10-05 11:13 ` Tony Lindgren
2015-10-05 12:19 ` Arnd Bergmann
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